Rusty Mountain (Japanese: てつさび山Rust Mountain) is a playable dungeon the player goes through in Pokémon Mystery Dungeon: Gates to Infinity. It has 25 floors and no boss. This dungeon is accessible after completing the main story-line. The 5th, 10th, and 15th floors hve a golden locked door surrounded by a poisonous cloud that all require a Poison and Steel-type Pokémon and 2,000 Poké to pass through.